The compensation due to a ship-owner from a freighter for unduly delaying his vessel in port beyond the time specified in the charter-party or bill of lading. It is in fact an extended freight. A ship unjustly detained, as a prize, is entitled to demurrage. Vessels chartered to convey government stores have a term given for discharge by government aid. If not delivered within that period, demurrage, as stated in the document, is paid per diem for any "unavoidable delay."